Top: Gilts, young female pigs that have yet to give birth, in their pen at the UC Davis swine center. Above: Josie Bradshaw rinses the gilts at the lab, which is studying pig behavior.

Top: Gilts, young female pigs that have yet to give birth, in their pen at the UC Davis swine center. Above: Josie Bradshaw rinses the gilts at the lab, which is studying pig behavior.

Photo: Nicole Boliaux, The Chronicle

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Piglets sleep in the nursery at the UC Davis Animal Science Swine Center on the day they were weaned.

Piglets sleep in the nursery at the UC Davis Animal Science Swine Center on the day they were weaned.

Photo: Nicole Boliaux, The Chronicle

New standards in animal welfare raise new issues

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Inside the swine research center at UC Davis, a pregnant black pig with an active pink-tipped snout chews on a metal bar. In more than 10,000 years of domestication, pigs haven’t lost their natural instinct to root for food, even in a cement-floored pen. That makes them constantly explore their environment with their nose and mouth, to the point of chewing on metal bars, and on each other.

“It’s an instinctual motor pattern — root, root, chew as much as you can,” says Kristina Horback, an assistant professor of applied ethology, or the study of animal behavior, at the department of animal science.

Horback is studying pig behaviors, such as incessant chewing, with the goal of making those pigs’ life at the farm better. Such quests to improve animal welfare will only grow in importance in the near future, as more and more consumers (and companies) opt for humanely raised meat. Within the next five to 10 years, major food companies such as McDonald’s and Smithfield Foods will hit self-imposed deadlines to stop buying or selling pork produced with gestation crates, the tight metal stalls that keep sows in one position for the majority of their lives. That has opened a Pandora’s box of questions about how to transition the animals to group housing — and how to humanely raise animals at a large, sustainable scale.

“These sows have been bred to perform well in crates,” says Horback, who is looking into how toys and different enclosures can better suit pigs’ social behavior, intelligence and physical needs. “And now we’re asking them to negotiate these social situations.”

In a way she’s helping farmers reintroduce old ways of pig farming for the industry of the future, with plans to develop research methods she can apply later to chicken and cattle, too.

“People still want to eat meat,” Horback says. “And they want to know their animals lived a good life.”

Gestation crates are used to produce 83 to 90 percent of American pork. The cages — 2 to 2½ feet wide and about 6½ feet long — have been banned in California and nine other states, although only one of those, Ohio, is a major pork producer.

Pigs have demonstrated complex behavior similar to dogs and chimpanzees, according to a 2015 review of research by Lori Marino and Christina Colvin of Emory University. They’re capable of playing basic computer games, doing puzzles and learning from each other. They’re also very hierarchical.

In the wild, mature males live solo while females travel in packs with their babies, with one dominant sow. When female strangers meet, they fight to determine who will be the alpha. So when you take the sows out of the crates, they jostle, often violently, over food and social order.

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“That was leading to a lot of injuries and abortions,” says Horback, which was one main reason gestation crates were introduced in the 1960s, when they were considered humane.

Horback completed a post-doc at the University of Pennsylvania with Professor Thomas Parsons. Parsons studies options for pig group housing, partly based on what’s being done in the European Union, which has had a partial ban on crates since 2013.

He helped Pennsylvania pork producer Clemens Food Group switch to open barns where sows hang out in hierarchical groups like cliques in the middle school cafeteria. Instead of the cafeteria line, they head to an individual eating stall that opens when activated by a tag on their ear.

Journalist Barry Estabrook visited the Clemens facility last year and says while “not hog heaven,” it’s definitely an improvement over constant crating.

“What we’re seeing here is ways for people to do it at large enough numbers and a low enough price to make it accessible to corporate and everyday shoppers,” says Estabrook, author of the 2015 book “Pig Tales: An Omnivore’s Quest for Sustainable Meat.”

Bon Appetit Management Co., the Palo Alto food-service company that runs cafeterias at museums, universities and companies like Google, switched to pork from Clemens last year, and now buys around 3.5 million pounds per year.

Consumers have said in surveys they’re willing to pay an average of 34 cents per pound more for pork not raised in gestation crates, while the added cost of production would be much less than that, according to a 2011 study by Lacey Seibert and F. Bailey Norwood of Oklahoma State University.

Here’s how a typical confinement farm works: Female pigs are first bred when they are 6 to 8 months old and live in a gestation crate during pregnancy, which lasts three months, three weeks and three days, give or take. When they give birth they’re moved to farrowing crates, which are larger than gestation crates to allow them to nurse their litters of around 10 to 12 piglets. After the piglets are weaned at around three weeks, the sows are then artificially inseminated again and returned to gestation crates almost immediately.

One alternate to the gestation crate on display at the UC Davis swine center opens in back so sows can enter during feeding time. The back automatically swings shut so they can eat in peace, but the pigs can then freely back out into a larger common area to socialize.

In another open pen, two pregnant sows nap snout on snout, making light snorts as if dream-talking to each other.

“This is their natural behavior,” Horback says of the pregnant sows. “At dawn and dusk they’re more busy, but they rest during the day.”

In the farrowing room, a large sow tries to nap after feeding her litter of 10. The piglets doze and climb over each other and their mother’s head. They’re in a farrowing crate, which in some cases has small bars that keep the sow from rolling on her babies but still allows them to nurse. Though some animal rights activists object to the crates, farmers say they prevent the sows from accidentally killing their piglets when turning over, and so there aren’t plans to phase them out on a wide scale.

In the litter, hierarchy starts immediately. Piglets always go to the same teat, with stronger piglets monopolizing ones with the most milk. That “teat rank” stays in place after they’re weaned and sent to the nursery. (That’s a point at which Horback has observed mothers running around joyfully back in the sow group pen, like parents who just dropped the kids off at summer camp.)

Horback and her team plop one of the piglets in a playpen with a loud battery-operated toy to see how she deals with the stress of encountering an unknown object.

“We want to figure out mental health issues,” she says, just like it’s done for elephants and primates in captivity, her area of research before farm animals. “Zoo animals are put on a pedestal. The same isn’t done for farm animals.”

She shows off a Bite-Rite, basically a piglet pacifier with several long tubes for weaned piglets to chew on. Adult females prefer gnawing on long ropes that can be hung in their open pens. The enrichments can be offered as an alternative to tail removal or docking, which is typically done to newborn pigs to keep them from chewing on each other’s tails, which often leads to infections.

These improvements are all promising, Estabrook says, but he cautions that corporate policies to improve welfare for pigs usually fall short of being “crate-free.” Most will still allow sows to be kept in crates for the first few weeks of pregnancy.

Some of the best practices, he says, are by farms that raise their pigs on pasture, or by producers such as Niman Ranch, which bans crates and requires farmers to house pigs outside or in hoop barns with hay bedding, which sows use to build a nest for their litters. Those housing methods, however, result in much more expensive pork.